As shown in FIG. 5 of "ATM exchange configuration scheme," Technical Report SSE89-53, The Institute of Electronics, Information and Communication Engineers, an ATM exchange forming an exchange node in an asynchronous transfer mode (ATM) network includes an ATM switch for transferring each of ATM cells inputted from a plurality of input ports to any one of a plurality of output ports according to header information of the cell, a line associated unit (a line interface) inserted between each of input/output ports of the ATM switch and an input/output line, a signal processor (communication controller) for converting ATM cells to a message or converting a message to ATM cells, and a call controller connected to the signal processor.
ATM cells for signalling received from each input line are inputted to the signal processor via the ATM switch, assembled into a message, and then transferred to the call controller.
The call controller includes a processor and a memory, and conducts an exchange process by using a stored programming control scheme. An exchange process program stored in the memory includes, for example, an origination analysis for determining whether origination of a call can be allowed, a digit analysis for translating a received address and determining a terminating destination, and a terminating line analysis to be conducted at the time of call termination.
In conventional ATM exchanges, all of the exchange process to be conducted since a call has occurred on an input/output line (a subscriber line or a trunk) until the call disappears is executed by a processor of the above described call controller incorporated in the exchange. Not only in the ATM exchanges but also in electronic exchanges using time division switches or space division switches, the exchange process is conducted in an equipment configuration similar to that described above.
However, the conventional equipment configuration has the following problems because the exchange process program is stored in the memory incorporated in the exchange.
(1) In the case where service contents in the exchange are to be changed (or added), it is necessary, no matter whether the scale of the change is large or small, to update an existing program file in a different place and download the updated file contents into the memory part of the above described exchange. Thus a lot of man power is required for amending the program.
(2) In the conventional call control processor of exchanges, an OS and a program language having special forms different from those of the OS and the program language typically used in user terminals are employed. For example, the CTRON is used as the OS, and the CHILL is used as the program language.
(3) Each exchange is controlled by a program incorporated in its call controller. Therefore, complicated control is needed for network-wide services extending over exchanges.
An object of the present invention is to provide such a packet exchange system and a packet communication network system that service contents in the exchange can be easily changed and added.
Another object of the present invention is to provide such a packet communication network system that network-wide services extending over a plurality of exchanges can be easily implemented.
Another object of the present invention is to provide a terminal having a function of communicating with another terminal and a function of controlling a packet exchange and capable of efficiently utilizing the data process capability.